<v-form v-model="valid" :class="visibleclass">
    <v-row no-gutters>
        <v-col cols="12" md="4">
            <v-text-field label="URL" v-model="value" @change="tfChange" :rules="urlRule" required :readonly="readonly">
            </v-text-field>
        </v-col>
    </v-row>
</v-form>